Stealth, which equates to signature management, plays an important part in the design of naval vessels. For surface vessels, the most important signatures are the optical signature, radar signature, infrared signature, and acoustic signature. These signatures are detectable by the sensors of other vessels, aircraft, missiles, and submarines.
The reduction of these signatures provides several important benefits to a vessel, including (1) decreasing the distance at which the vessel can be detected, thereby increasing the likelihood that the vessel will detect others first; (2) obfuscating the true size, shape, type and characteristics of the vessel; and (3) improving the likelihood that decoy and chaff ammunition will be effective in diverting incoming missiles.
The radar signature is measured as radar cross section (“RCS”) in dB/m2. Stealth shaping via the use of flat inclined surfaces and the avoidance of corner reflectors has substantially reduced the RCS of naval vessels. In fact, the RCS of the vessel's deck equipment is now typically greater than that of the vessel itself.
One potentially significant contributor to a vessel's RCS is its on-deck missile launch system. To address this, in-deck vertical missile launchers, such as the MK 41 Vertical Launch System, have been developed. Since in-deck launch systems are below the surface of the deck, they have virtually no impact on the vessel's RCS.
Most ship-borne missiles are vertically launched, but there are some missiles that must be launched at an inclined angle (i.e., less than ninety degrees). Since in-deck, vertical missile launchers cannot be used to launch these missiles, a deck-mounted launcher, with its greater RCS, is typically used.
In one type of deck-mounted, inclined missile-launch system, missile canisters are permanently fixed at an appropriate launch angle by a fixed-angle launch structure. This type of launcher presents a large RCS.
Another type of deck-mounted, inclined missile-launch system, includes a tilting launch structure. An example of this type of system is the armored box launcher. This system includes a launch structure that supports the missile canisters and is capable of tilting them between a pre-launch orientation in which they are substantially parallel to the deck of the ship and a launch orientation in which the canisters are inclined to an appropriate launch angle.
Although the armored box launcher does not maintain a fixed launch angle, it nevertheless has a large RCS as a consequence of its sharp corners and boxy structure.
A need therefore exists for an inclined missile launcher that has a relatively low RCS.